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.TH "KDC.CONF" "5" " " "1.21" "MIT Kerberos"
.SH NAME
kdc.conf \- Kerberos V5 KDC configuration file
.
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.sp
The kdc.conf file supplements krb5.conf(5) for programs which
are typically only used on a KDC, such as the krb5kdc(8) and
kadmind(8) daemons and the kdb5_util(8) program.
Relations documented here may also be specified in krb5.conf; for the
KDC programs mentioned, krb5.conf and kdc.conf will be merged into a
single configuration profile.
.sp
Normally, the kdc.conf file is found in the KDC state directory,
\fB@LOCALSTATEDIR@\fP\fB/krb5kdc\fP\&.  You can override the default location by setting the
environment variable \fBKRB5_KDC_PROFILE\fP\&.
.sp
Please note that you need to restart the KDC daemon for any configuration
changes to take effect.
.SH STRUCTURE
.sp
The kdc.conf file is set up in the same format as the
krb5.conf(5) file.
.SH SECTIONS
.sp
The kdc.conf file may contain the following sections:
.TS
center;
|l|l|.
_
T{
\fI\%[kdcdefaults]\fP
T}	T{
Default values for KDC behavior
T}
_
T{
\fI\%[realms]\fP
T}	T{
Realm\-specific database configuration and settings
T}
_
T{
\fI\%[dbdefaults]\fP
T}	T{
Default database settings
T}
_
T{
\fI\%[dbmodules]\fP
T}	T{
Per\-database settings
T}
_
T{
\fI\%[logging]\fP
T}	T{
Controls how Kerberos daemons perform logging
T}
_
.TE
.SS [kdcdefaults]
.sp
Some relations in the [kdcdefaults] section specify default values for
realm variables, to be used if the [realms] subsection does not
contain a relation for the tag.  See the \fI\%[realms]\fP section for
the definitions of these relations.
.INDENT 0.0
.IP \(bu 2
\fBhost_based_services\fP
.IP \(bu 2
\fBkdc_listen\fP
.IP \(bu 2
\fBkdc_ports\fP
.IP \(bu 2
\fBkdc_tcp_listen\fP
.IP \(bu 2
\fBkdc_tcp_ports\fP
.IP \(bu 2
\fBno_host_referral\fP
.IP \(bu 2
\fBrestrict_anonymous_to_tgt\fP
.UNINDENT
.sp
The following [kdcdefaults] variables have no per\-realm equivalent:
.INDENT 0.0
.TP
\fBkdc_max_dgram_reply_size\fP
Specifies the maximum packet size that can be sent over UDP.  The
default value is 4096 bytes.
.TP
\fBkdc_tcp_listen_backlog\fP
(Integer.)  Set the size of the listen queue length for the KDC
daemon.  The value may be limited by OS settings.  The default
value is 5.
.TP
\fBspake_preauth_kdc_challenge\fP
(String.)  Specifies the group for a SPAKE optimistic challenge.
See the \fBspake_preauth_groups\fP variable in libdefaults
for possible values.  The default is not to issue an optimistic
challenge.  (New in release 1.17.)
.UNINDENT
.SS [realms]
.sp
Each tag in the [realms] section is the name of a Kerberos realm.  The
value of the tag is a subsection where the relations define KDC
parameters for that particular realm.  The following example shows how
to define one parameter for the ATHENA.MIT.EDU realm:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
[realms]
    ATHENA.MIT.EDU = {
        max_renewable_life = 7d 0h 0m 0s
    }
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
The following tags may be specified in a [realms] subsection:
.INDENT 0.0
.TP
\fBacl_file\fP
(String.)  Location of the access control list file that
kadmind(8) uses to determine which principals are allowed
which permissions on the Kerberos database.  To operate without an
ACL file, set this relation to the empty string with \fBacl_file =
""\fP\&.  The default value is \fB@LOCALSTATEDIR@\fP\fB/krb5kdc\fP\fB/kadm5.acl\fP\&.  For more
information on Kerberos ACL file see kadm5.acl(5)\&.
.TP
\fBdatabase_module\fP
(String.)  This relation indicates the name of the configuration
section under \fI\%[dbmodules]\fP for database\-specific parameters
used by the loadable database library.  The default value is the
realm name.  If this configuration section does not exist, default
values will be used for all database parameters.
.TP
\fBdatabase_name\fP
(String, deprecated.)  This relation specifies the location of the
Kerberos database for this realm, if the DB2 module is being used
and the \fI\%[dbmodules]\fP configuration section does not specify a
database name.  The default value is \fB@LOCALSTATEDIR@\fP\fB/krb5kdc\fP\fB/principal\fP\&.
.TP
\fBdefault_principal_expiration\fP
(abstime string.)  Specifies the default expiration date of
principals created in this realm.  The default value is 0, which
means no expiration date.
.TP
\fBdefault_principal_flags\fP
(Flag string.)  Specifies the default attributes of principals
created in this realm.  The format for this string is a
comma\-separated list of flags, with \(aq+\(aq before each flag that
should be enabled and \(aq\-\(aq before each flag that should be
disabled.  The \fBpostdateable\fP, \fBforwardable\fP, \fBtgt\-based\fP,
\fBrenewable\fP, \fBproxiable\fP, \fBdup\-skey\fP, \fBallow\-tickets\fP, and
\fBservice\fP flags default to enabled.
.sp
There are a number of possible flags:
.INDENT 7.0
.TP
\fBallow\-tickets\fP
Enabling this flag means that the KDC will issue tickets for
this principal.  Disabling this flag essentially deactivates
the principal within this realm.
.TP
\fBdup\-skey\fP
Enabling this flag allows the KDC to issue user\-to\-user
service tickets for this principal.
.TP
\fBforwardable\fP
Enabling this flag allows the principal to obtain forwardable
tickets.
.TP
\fBhwauth\fP
If this flag is enabled, then the principal is required to
preauthenticate using a hardware device before receiving any
tickets.
.TP
\fBno\-auth\-data\-required\fP
Enabling this flag prevents PAC or AD\-SIGNEDPATH data from
being added to service tickets for the principal.
.TP
\fBok\-as\-delegate\fP
If this flag is enabled, it hints the client that credentials
can and should be delegated when authenticating to the
service.
.TP
\fBok\-to\-auth\-as\-delegate\fP
Enabling this flag allows the principal to use S4USelf tickets.
.TP
\fBpostdateable\fP
Enabling this flag allows the principal to obtain postdateable
tickets.
.TP
\fBpreauth\fP
If this flag is enabled on a client principal, then that
principal is required to preauthenticate to the KDC before
receiving any tickets.  On a service principal, enabling this
flag means that service tickets for this principal will only
be issued to clients with a TGT that has the preauthenticated
bit set.
.TP
\fBproxiable\fP
Enabling this flag allows the principal to obtain proxy
tickets.
.TP
\fBpwchange\fP
Enabling this flag forces a password change for this
principal.
.TP
\fBpwservice\fP
If this flag is enabled, it marks this principal as a password
change service.  This should only be used in special cases,
for example, if a user\(aqs password has expired, then the user
has to get tickets for that principal without going through
the normal password authentication in order to be able to
change the password.
.TP
\fBrenewable\fP
Enabling this flag allows the principal to obtain renewable
tickets.
.TP
\fBservice\fP
Enabling this flag allows the the KDC to issue service tickets
for this principal.  In release 1.17 and later, user\-to\-user
service tickets are still allowed if the \fBdup\-skey\fP flag is
set.
.TP
\fBtgt\-based\fP
Enabling this flag allows a principal to obtain tickets based
on a ticket\-granting\-ticket, rather than repeating the
authentication process that was used to obtain the TGT.
.UNINDENT
.TP
\fBdict_file\fP
(String.)  Location of the dictionary file containing strings that
are not allowed as passwords.  The file should contain one string
per line, with no additional whitespace.  If none is specified or
if there is no policy assigned to the principal, no dictionary
checks of passwords will be performed.
.TP
\fBdisable_pac\fP
(Boolean value.)  If true, the KDC will not issue PACs for this
realm, and S4U2Self and S4U2Proxy operations will be disabled.
The default is false, which will permit the KDC to issue PACs.
New in release 1.20.
.TP
\fBencrypted_challenge_indicator\fP
(String.)  Specifies the authentication indicator value that the KDC
asserts into tickets obtained using FAST encrypted challenge
pre\-authentication.  New in 1.16.
.TP
\fBhost_based_services\fP
(Whitespace\- or comma\-separated list.)  Lists services which will
get host\-based referral processing even if the server principal is
not marked as host\-based by the client.
.TP
\fBiprop_enable\fP
(Boolean value.)  Specifies whether incremental database
propagation is enabled.  The default value is false.
.TP
\fBiprop_ulogsize\fP
(Integer.)  Specifies the maximum number of log entries to be
retained for incremental propagation.  The default value is 1000.
Prior to release 1.11, the maximum value was 2500.  New in release
1.19.
.TP
\fBiprop_master_ulogsize\fP
The name for \fBiprop_ulogsize\fP prior to release 1.19.  Its value is
used as a fallback if \fBiprop_ulogsize\fP is not specified.
.TP
\fBiprop_replica_poll\fP
(Delta time string.)  Specifies how often the replica KDC polls
for new updates from the primary.  The default value is \fB2m\fP
(that is, two minutes).  New in release 1.17.
.TP
\fBiprop_slave_poll\fP
(Delta time string.)  The name for \fBiprop_replica_poll\fP prior to
release 1.17.  Its value is used as a fallback if
\fBiprop_replica_poll\fP is not specified.
.TP
\fBiprop_listen\fP
(Whitespace\- or comma\-separated list.)  Specifies the iprop RPC
listening addresses and/or ports for the kadmind(8) daemon.
Each entry may be an interface address, a port number, or an
address and port number separated by a colon.  If the address
contains colons, enclose it in square brackets.  If no address is
specified, the wildcard address is used.  If kadmind fails to bind
to any of the specified addresses, it will fail to start.  The
default (when \fBiprop_enable\fP is true) is to bind to the wildcard
address at the port specified in \fBiprop_port\fP\&.  New in release
1.15.
.TP
\fBiprop_port\fP
(Port number.)  Specifies the port number to be used for
incremental propagation.  When \fBiprop_enable\fP is true, this
relation is required in the replica KDC configuration file, and
this relation or \fBiprop_listen\fP is required in the primary
configuration file, as there is no default port number.  Port
numbers specified in \fBiprop_listen\fP entries will override this
port number for the kadmind(8) daemon.
.TP
\fBiprop_resync_timeout\fP
(Delta time string.)  Specifies the amount of time to wait for a
full propagation to complete.  This is optional in configuration
files, and is used by replica KDCs only.  The default value is 5
minutes (\fB5m\fP).  New in release 1.11.
.TP
\fBiprop_logfile\fP
(File name.)  Specifies where the update log file for the realm
database is to be stored.  The default is to use the
\fBdatabase_name\fP entry from the realms section of the krb5 config
file, with \fB\&.ulog\fP appended.  (NOTE: If \fBdatabase_name\fP isn\(aqt
specified in the realms section, perhaps because the LDAP database
back end is being used, or the file name is specified in the
[dbmodules] section, then the hard\-coded default for
\fBdatabase_name\fP is used.  Determination of the \fBiprop_logfile\fP
default value will not use values from the [dbmodules] section.)
.TP
\fBkadmind_listen\fP
(Whitespace\- or comma\-separated list.)  Specifies the kadmin RPC
listening addresses and/or ports for the kadmind(8) daemon.
Each entry may be an interface address, a port number, or an
address and port number separated by a colon.  If the address
contains colons, enclose it in square brackets.  If no address is
specified, the wildcard address is used.  If kadmind fails to bind
to any of the specified addresses, it will fail to start.  The
default is to bind to the wildcard address at the port specified
in \fBkadmind_port\fP, or the standard kadmin port (749).  New in
release 1.15.
.TP
\fBkadmind_port\fP
(Port number.)  Specifies the port on which the kadmind(8)
daemon is to listen for this realm.  Port numbers specified in
\fBkadmind_listen\fP entries will override this port number.  The
assigned port for kadmind is 749, which is used by default.
.TP
\fBkey_stash_file\fP
(String.)  Specifies the location where the master key has been
stored (via kdb5_util stash).  The default is \fB@LOCALSTATEDIR@\fP\fB/krb5kdc\fP\fB/.k5.REALM\fP, where \fIREALM\fP is the Kerberos realm.
.TP
\fBkdc_listen\fP
(Whitespace\- or comma\-separated list.)  Specifies the UDP
listening addresses and/or ports for the krb5kdc(8) daemon.
Each entry may be an interface address, a port number, or an
address and port number separated by a colon.  If the address
contains colons, enclose it in square brackets.  If no address is
specified, the wildcard address is used.  If no port is specified,
the standard port (88) is used.  If the KDC daemon fails to bind
to any of the specified addresses, it will fail to start.  The
default is to bind to the wildcard address on the standard port.
New in release 1.15.
.TP
\fBkdc_ports\fP
(Whitespace\- or comma\-separated list, deprecated.)  Prior to
release 1.15, this relation lists the ports for the
krb5kdc(8) daemon to listen on for UDP requests.  In
release 1.15 and later, it has the same meaning as \fBkdc_listen\fP
if that relation is not defined.
.TP
\fBkdc_tcp_listen\fP
(Whitespace\- or comma\-separated list.)  Specifies the TCP
listening addresses and/or ports for the krb5kdc(8) daemon.
Each entry may be an interface address, a port number, or an
address and port number separated by a colon.  If the address
contains colons, enclose it in square brackets.  If no address is
specified, the wildcard address is used.  If no port is specified,
the standard port (88) is used.  To disable listening on TCP, set
this relation to the empty string with \fBkdc_tcp_listen = ""\fP\&.
If the KDC daemon fails to bind to any of the specified addresses,
it will fail to start.  The default is to bind to the wildcard
address on the standard port.  New in release 1.15.
.TP
\fBkdc_tcp_ports\fP
(Whitespace\- or comma\-separated list, deprecated.)  Prior to
release 1.15, this relation lists the ports for the
krb5kdc(8) daemon to listen on for UDP requests.  In
release 1.15 and later, it has the same meaning as
\fBkdc_tcp_listen\fP if that relation is not defined.
.TP
\fBkpasswd_listen\fP
(Comma\-separated list.)  Specifies the kpasswd listening addresses
and/or ports for the kadmind(8) daemon.  Each entry may be
an interface address, a port number, or an address and port number
separated by a colon.  If the address contains colons, enclose it
in square brackets.  If no address is specified, the wildcard
address is used.  If kadmind fails to bind to any of the specified
addresses, it will fail to start.  The default is to bind to the
wildcard address at the port specified in \fBkpasswd_port\fP, or the
standard kpasswd port (464).  New in release 1.15.
.TP
\fBkpasswd_port\fP
(Port number.)  Specifies the port on which the kadmind(8)
daemon is to listen for password change requests for this realm.
Port numbers specified in \fBkpasswd_listen\fP entries will override
this port number.  The assigned port for password change requests
is 464, which is used by default.
.TP
\fBmaster_key_name\fP
(String.)  Specifies the name of the principal associated with the
master key.  The default is \fBK/M\fP\&.
.TP
\fBmaster_key_type\fP
(Key type string.)  Specifies the master key\(aqs key type.  The
default value for this is \fBaes256\-cts\-hmac\-sha1\-96\fP\&.  For a list of all possible
values, see \fI\%Encryption types\fP\&.
.TP
\fBmax_life\fP
(duration string.)  Specifies the maximum time period for
which a ticket may be valid in this realm.  The default value is
24 hours.
.TP
\fBmax_renewable_life\fP
(duration string.)  Specifies the maximum time period
during which a valid ticket may be renewed in this realm.
The default value is 0.
.TP
\fBno_host_referral\fP
(Whitespace\- or comma\-separated list.)  Lists services to block
from getting host\-based referral processing, even if the client
marks the server principal as host\-based or the service is also
listed in \fBhost_based_services\fP\&.  \fBno_host_referral = *\fP will
disable referral processing altogether.
.TP
\fBreject_bad_transit\fP
(Boolean value.)  If set to true, the KDC will check the list of
transited realms for cross\-realm tickets against the transit path
computed from the realm names and the capaths section of its
krb5.conf(5) file; if the path in the ticket to be issued
contains any realms not in the computed path, the ticket will not
be issued, and an error will be returned to the client instead.
If this value is set to false, such tickets will be issued
anyways, and it will be left up to the application server to
validate the realm transit path.
.sp
If the disable\-transited\-check flag is set in the incoming
request, this check is not performed at all.  Having the
\fBreject_bad_transit\fP option will cause such ticket requests to
be rejected always.
.sp
This transit path checking and config file option currently apply
only to TGS requests.
.sp
The default value is true.
.TP
\fBrestrict_anonymous_to_tgt\fP
(Boolean value.)  If set to true, the KDC will reject ticket
requests from anonymous principals to service principals other
than the realm\(aqs ticket\-granting service.  This option allows
anonymous PKINIT to be enabled for use as FAST armor tickets
without allowing anonymous authentication to services.  The
default value is false.  New in release 1.9.
.TP
\fBspake_preauth_indicator\fP
(String.)  Specifies an authentication indicator value that the
KDC asserts into tickets obtained using SPAKE pre\-authentication.
The default is not to add any indicators.  This option may be
specified multiple times.  New in release 1.17.
.TP
\fBsupported_enctypes\fP
(List of \fIkey\fP:\fIsalt\fP strings.)  Specifies the default key/salt
combinations of principals for this realm.  Any principals created
through kadmin(1) will have keys of these types.  The
default value for this tag is \fBaes256\-cts\-hmac\-sha1\-96:normal aes128\-cts\-hmac\-sha1\-96:normal\fP\&.  For lists of
possible values, see \fI\%Keysalt lists\fP\&.
.UNINDENT
.SS [dbdefaults]
.sp
The [dbdefaults] section specifies default values for some database
parameters, to be used if the [dbmodules] subsection does not contain
a relation for the tag.  See the \fI\%[dbmodules]\fP section for the
definitions of these relations.
.INDENT 0.0
.IP \(bu 2
\fBldap_kerberos_container_dn\fP
.IP \(bu 2
\fBldap_kdc_dn\fP
.IP \(bu 2
\fBldap_kdc_sasl_authcid\fP
.IP \(bu 2
\fBldap_kdc_sasl_authzid\fP
.IP \(bu 2
\fBldap_kdc_sasl_mech\fP
.IP \(bu 2
\fBldap_kdc_sasl_realm\fP
.IP \(bu 2
\fBldap_kadmind_dn\fP
.IP \(bu 2
\fBldap_kadmind_sasl_authcid\fP
.IP \(bu 2
\fBldap_kadmind_sasl_authzid\fP
.IP \(bu 2
\fBldap_kadmind_sasl_mech\fP
.IP \(bu 2
\fBldap_kadmind_sasl_realm\fP
.IP \(bu 2
\fBldap_service_password_file\fP
.IP \(bu 2
\fBldap_conns_per_server\fP
.UNINDENT
.SS [dbmodules]
.sp
The [dbmodules] section contains parameters used by the KDC database
library and database modules.  Each tag in the [dbmodules] section is
the name of a Kerberos realm or a section name specified by a realm\(aqs
\fBdatabase_module\fP parameter.  The following example shows how to
define one database parameter for the ATHENA.MIT.EDU realm:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
[dbmodules]
    ATHENA.MIT.EDU = {
        disable_last_success = true
    }
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
The following tags may be specified in a [dbmodules] subsection:
.INDENT 0.0
.TP
\fBdatabase_name\fP
This DB2\-specific tag indicates the location of the database in
the filesystem.  The default is \fB@LOCALSTATEDIR@\fP\fB/krb5kdc\fP\fB/principal\fP\&.
.TP
\fBdb_library\fP
This tag indicates the name of the loadable database module.  The
value should be \fBdb2\fP for the DB2 module, \fBklmdb\fP for the LMDB
module, or \fBkldap\fP for the LDAP module.
.TP
\fBdisable_last_success\fP
If set to \fBtrue\fP, suppresses KDC updates to the "Last successful
authentication" field of principal entries requiring
preauthentication.  Setting this flag may improve performance.
(Principal entries which do not require preauthentication never
update the "Last successful authentication" field.).  First
introduced in release 1.9.
.TP
\fBdisable_lockout\fP
If set to \fBtrue\fP, suppresses KDC updates to the "Last failed
authentication" and "Failed password attempts" fields of principal
entries requiring preauthentication.  Setting this flag may
improve performance, but also disables account lockout.  First
introduced in release 1.9.
.TP
\fBldap_conns_per_server\fP
This LDAP\-specific tag indicates the number of connections to be
maintained per LDAP server.
.TP
\fBldap_kdc_dn\fP and \fBldap_kadmind_dn\fP
These LDAP\-specific tags indicate the default DN for binding to
the LDAP server.  The krb5kdc(8) daemon uses
\fBldap_kdc_dn\fP, while the kadmind(8) daemon and other
administrative programs use \fBldap_kadmind_dn\fP\&.  The kadmind DN
must have the rights to read and write the Kerberos data in the
LDAP database.  The KDC DN must have the same rights, unless
\fBdisable_lockout\fP and \fBdisable_last_success\fP are true, in
which case it only needs to have rights to read the Kerberos data.
These tags are ignored if a SASL mechanism is set with
\fBldap_kdc_sasl_mech\fP or \fBldap_kadmind_sasl_mech\fP\&.
.TP
\fBldap_kdc_sasl_mech\fP and \fBldap_kadmind_sasl_mech\fP
These LDAP\-specific tags specify the SASL mechanism (such as
\fBEXTERNAL\fP) to use when binding to the LDAP server.  New in
release 1.13.
.TP
\fBldap_kdc_sasl_authcid\fP and \fBldap_kadmind_sasl_authcid\fP
These LDAP\-specific tags specify the SASL authentication identity
to use when binding to the LDAP server.  Not all SASL mechanisms
require an authentication identity.  If the SASL mechanism
requires a secret (such as the password for \fBDIGEST\-MD5\fP), these
tags also determine the name within the
\fBldap_service_password_file\fP where the secret is stashed.  New
in release 1.13.
.TP
\fBldap_kdc_sasl_authzid\fP and \fBldap_kadmind_sasl_authzid\fP
These LDAP\-specific tags specify the SASL authorization identity
to use when binding to the LDAP server.  In most circumstances
they do not need to be specified.  New in release 1.13.
.TP
\fBldap_kdc_sasl_realm\fP and \fBldap_kadmind_sasl_realm\fP
These LDAP\-specific tags specify the SASL realm to use when
binding to the LDAP server.  In most circumstances they do not
need to be set.  New in release 1.13.
.TP
\fBldap_kerberos_container_dn\fP
This LDAP\-specific tag indicates the DN of the container object
where the realm objects will be located.
.TP
\fBldap_servers\fP
This LDAP\-specific tag indicates the list of LDAP servers that the
Kerberos servers can connect to.  The list of LDAP servers is
whitespace\-separated.  The LDAP server is specified by a LDAP URI.
It is recommended to use \fBldapi:\fP or \fBldaps:\fP URLs to connect
to the LDAP server.
.TP
\fBldap_service_password_file\fP
This LDAP\-specific tag indicates the file containing the stashed
passwords (created by \fBkdb5_ldap_util stashsrvpw\fP) for the
\fBldap_kdc_dn\fP and \fBldap_kadmind_dn\fP objects, or for the
\fBldap_kdc_sasl_authcid\fP or \fBldap_kadmind_sasl_authcid\fP names
for SASL authentication.  This file must be kept secure.
.TP
\fBmapsize\fP
This LMDB\-specific tag indicates the maximum size of the two
database environments in megabytes.  The default value is 128.
Increase this value to address "Environment mapsize limit reached"
errors.  New in release 1.17.
.TP
\fBmax_readers\fP
This LMDB\-specific tag indicates the maximum number of concurrent
reading processes for the databases.  The default value is 128.
New in release 1.17.
.TP
\fBnosync\fP
This LMDB\-specific tag can be set to improve the throughput of
kadmind and other administrative agents, at the expense of
durability (recent database changes may not survive a power outage
or other sudden reboot).  It does not affect the throughput of the
KDC.  The default value is false.  New in release 1.17.
.TP
\fBunlockiter\fP
If set to \fBtrue\fP, this DB2\-specific tag causes iteration
operations to release the database lock while processing each
principal.  Setting this flag to \fBtrue\fP can prevent extended
blocking of KDC or kadmin operations when dumps of large databases
are in progress.  First introduced in release 1.13.
.UNINDENT
.sp
The following tag may be specified directly in the [dbmodules]
section to control where database modules are loaded from:
.INDENT 0.0
.TP
\fBdb_module_dir\fP
This tag controls where the plugin system looks for database
modules.  The value should be an absolute path.
.UNINDENT
.SS [logging]
.sp
The [logging] section indicates how krb5kdc(8) and
kadmind(8) perform logging.  It may contain the following
relations:
.INDENT 0.0
.TP
\fBadmin_server\fP
Specifies how kadmind(8) performs logging.
.TP
\fBkdc\fP
Specifies how krb5kdc(8) performs logging.
.TP
\fBdefault\fP
Specifies how either daemon performs logging in the absence of
relations specific to the daemon.
.TP
\fBdebug\fP
(Boolean value.)  Specifies whether debugging messages are
included in log outputs other than SYSLOG.  Debugging messages are
always included in the system log output because syslog performs
its own priority filtering.  The default value is false.  New in
release 1.15.
.UNINDENT
.sp
Logging specifications may have the following forms:
.INDENT 0.0
.TP
\fBFILE=\fP\fIfilename\fP or \fBFILE:\fP\fIfilename\fP
This value causes the daemon\(aqs logging messages to go to the
\fIfilename\fP\&.  If the \fB=\fP form is used, the file is overwritten.
If the \fB:\fP form is used, the file is appended to.
.TP
\fBSTDERR\fP
This value causes the daemon\(aqs logging messages to go to its
standard error stream.
.TP
\fBCONSOLE\fP
This value causes the daemon\(aqs logging messages to go to the
console, if the system supports it.
.TP
\fBDEVICE=\fP\fI<devicename>\fP
This causes the daemon\(aqs logging messages to go to the specified
device.
.TP
\fBSYSLOG\fP[\fB:\fP\fIseverity\fP[\fB:\fP\fIfacility\fP]]
This causes the daemon\(aqs logging messages to go to the system log.
.sp
For backward compatibility, a severity argument may be specified,
and must be specified in order to specify a facility.  This
argument will be ignored.
.sp
The facility argument specifies the facility under which the
messages are logged.  This may be any of the following facilities
supported by the syslog(3) call minus the LOG_ prefix: \fBKERN\fP,
\fBUSER\fP, \fBMAIL\fP, \fBDAEMON\fP, \fBAUTH\fP, \fBLPR\fP, \fBNEWS\fP,
\fBUUCP\fP, \fBCRON\fP, and \fBLOCAL0\fP through \fBLOCAL7\fP\&.  If no
facility is specified, the default is \fBAUTH\fP\&.
.UNINDENT
.sp
In the following example, the logging messages from the KDC will go to
the console and to the system log under the facility LOG_DAEMON, and
the logging messages from the administrative server will be appended
to the file \fB/var/adm/kadmin.log\fP and sent to the device
\fB/dev/tty04\fP\&.
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
[logging]
    kdc = CONSOLE
    kdc = SYSLOG:INFO:DAEMON
    admin_server = FILE:/var/adm/kadmin.log
    admin_server = DEVICE=/dev/tty04
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
If no logging specification is given, the default is to use syslog.
To disable logging entirely, specify \fBdefault = DEVICE=/dev/null\fP\&.
.SS [otp]
.sp
Each subsection of [otp] is the name of an OTP token type.  The tags
within the subsection define the configuration required to forward a
One Time Password request to a RADIUS server.
.sp
For each token type, the following tags may be specified:
.INDENT 0.0
.TP
\fBserver\fP
This is the server to send the RADIUS request to.  It can be a
hostname with optional port, an ip address with optional port, or
a Unix domain socket address.  The default is
\fB@LOCALSTATEDIR@\fP\fB/krb5kdc\fP\fB/<name>.socket\fP\&.
.TP
\fBsecret\fP
This tag indicates a filename (which may be relative to \fB@LOCALSTATEDIR@\fP\fB/krb5kdc\fP)
containing the secret used to encrypt the RADIUS packets.  The
secret should appear in the first line of the file by itself;
leading and trailing whitespace on the line will be removed.  If
the value of \fBserver\fP is a Unix domain socket address, this tag
is optional, and an empty secret will be used if it is not
specified.  Otherwise, this tag is required.
.TP
\fBtimeout\fP
An integer which specifies the time in seconds during which the
KDC should attempt to contact the RADIUS server.  This tag is the
total time across all retries and should be less than the time
which an OTP value remains valid for.  The default is 5 seconds.
.TP
\fBretries\fP
This tag specifies the number of retries to make to the RADIUS
server.  The default is 3 retries (4 tries).
.TP
\fBstrip_realm\fP
If this tag is \fBtrue\fP, the principal without the realm will be
passed to the RADIUS server.  Otherwise, the realm will be
included.  The default value is \fBtrue\fP\&.
.TP
\fBindicator\fP
This tag specifies an authentication indicator to be included in
the ticket if this token type is used to authenticate.  This
option may be specified multiple times.  (New in release 1.14.)
.UNINDENT
.sp
In the following example, requests are sent to a remote server via UDP:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
[otp]
    MyRemoteTokenType = {
        server = radius.mydomain.com:1812
        secret = SEmfiajf42$
        timeout = 15
        retries = 5
        strip_realm = true
    }
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
An implicit default token type named \fBDEFAULT\fP is defined for when
the per\-principal configuration does not specify a token type.  Its
configuration is shown below.  You may override this token type to
something applicable for your situation:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
[otp]
    DEFAULT = {
        strip_realm = false
    }
.ft P
.fi
.UNINDENT
.UNINDENT
.SH PKINIT OPTIONS
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The following are pkinit\-specific options.  These values may
be specified in [kdcdefaults] as global defaults, or within
a realm\-specific subsection of [realms].  Also note that a
realm\-specific value over\-rides, does not add to, a generic
[kdcdefaults] specification.  The search order is:
.UNINDENT
.UNINDENT
.INDENT 0.0
.IP 1. 3
realm\-specific subsection of [realms]:
.INDENT 3.0
.INDENT 3.5
.sp
.nf
.ft C
[realms]
    EXAMPLE.COM = {
        pkinit_anchors = FILE:/usr/local/example.com.crt
    }
.ft P
.fi
.UNINDENT
.UNINDENT
.IP 2. 3
generic value in the [kdcdefaults] section:
.INDENT 3.0
.INDENT 3.5
.sp
.nf
.ft C
[kdcdefaults]
    pkinit_anchors = DIR:/usr/local/generic_trusted_cas/
.ft P
.fi
.UNINDENT
.UNINDENT
.UNINDENT
.sp
For information about the syntax of some of these options, see
Specifying PKINIT identity information in
krb5.conf(5)\&.
.INDENT 0.0
.TP
\fBpkinit_anchors\fP
Specifies the location of trusted anchor (root) certificates which
the KDC trusts to sign client certificates.  This option is
required if pkinit is to be supported by the KDC.  This option may
be specified multiple times.
.TP
\fBpkinit_dh_min_bits\fP
Specifies the minimum number of bits the KDC is willing to accept
for a client\(aqs Diffie\-Hellman key.  The default is 2048.
.TP
\fBpkinit_allow_upn\fP
Specifies that the KDC is willing to accept client certificates
with the Microsoft UserPrincipalName (UPN) Subject Alternative
Name (SAN).  This means the KDC accepts the binding of the UPN in
the certificate to the Kerberos principal name.  The default value
is false.
.sp
Without this option, the KDC will only accept certificates with
the id\-pkinit\-san as defined in \fI\%RFC 4556\fP\&.  There is currently
no option to disable SAN checking in the KDC.
.TP
\fBpkinit_eku_checking\fP
This option specifies what Extended Key Usage (EKU) values the KDC
is willing to accept in client certificates.  The values
recognized in the kdc.conf file are:
.INDENT 7.0
.TP
\fBkpClientAuth\fP
This is the default value and specifies that client
certificates must have the id\-pkinit\-KPClientAuth EKU as
defined in \fI\%RFC 4556\fP\&.
.TP
\fBscLogin\fP
If scLogin is specified, client certificates with the
Microsoft Smart Card Login EKU (id\-ms\-kp\-sc\-logon) will be
accepted.
.TP
\fBnone\fP
If none is specified, then client certificates will not be
checked to verify they have an acceptable EKU.  The use of
this option is not recommended.
.UNINDENT
.TP
\fBpkinit_identity\fP
Specifies the location of the KDC\(aqs X.509 identity information.
This option is required if pkinit is to be supported by the KDC.
.TP
\fBpkinit_indicator\fP
Specifies an authentication indicator to include in the ticket if
pkinit is used to authenticate.  This option may be specified
multiple times.  (New in release 1.14.)
.TP
\fBpkinit_pool\fP
Specifies the location of intermediate certificates which may be
used by the KDC to complete the trust chain between a client\(aqs
certificate and a trusted anchor.  This option may be specified
multiple times.
.TP
\fBpkinit_revoke\fP
Specifies the location of Certificate Revocation List (CRL)
information to be used by the KDC when verifying the validity of
client certificates.  This option may be specified multiple times.
.TP
\fBpkinit_require_crl_checking\fP
The default certificate verification process will always check the
available revocation information to see if a certificate has been
revoked.  If a match is found for the certificate in a CRL,
verification fails.  If the certificate being verified is not
listed in a CRL, or there is no CRL present for its issuing CA,
and \fBpkinit_require_crl_checking\fP is false, then verification
succeeds.
.sp
However, if \fBpkinit_require_crl_checking\fP is true and there is
no CRL information available for the issuing CA, then verification
fails.
.sp
\fBpkinit_require_crl_checking\fP should be set to true if the
policy is such that up\-to\-date CRLs must be present for every CA.
.TP
\fBpkinit_require_freshness\fP
Specifies whether to require clients to include a freshness token
in PKINIT requests.  The default value is false.  (New in release
1.17.)
.UNINDENT
.SH ENCRYPTION TYPES
.sp
Any tag in the configuration files which requires a list of encryption
types can be set to some combination of the following strings.
Encryption types marked as "weak" and "deprecated" are available for
compatibility but not recommended for use.
.TS
center;
|l|l|.
_
T{
des3\-cbc\-raw
T}	T{
Triple DES cbc mode raw (weak)
T}
_
T{
des3\-cbc\-sha1 des3\-hmac\-sha1 des3\-cbc\-sha1\-kd
T}	T{
Triple DES cbc mode with HMAC/sha1 (deprecated)
T}
_
T{
aes256\-cts\-hmac\-sha1\-96 aes256\-cts aes256\-sha1
T}	T{
AES\-256 CTS mode with 96\-bit SHA\-1 HMAC
T}
_
T{
aes128\-cts\-hmac\-sha1\-96 aes128\-cts aes128\-sha1
T}	T{
AES\-128 CTS mode with 96\-bit SHA\-1 HMAC
T}
_
T{
aes256\-cts\-hmac\-sha384\-192 aes256\-sha2
T}	T{
AES\-256 CTS mode with 192\-bit SHA\-384 HMAC
T}
_
T{
aes128\-cts\-hmac\-sha256\-128 aes128\-sha2
T}	T{
AES\-128 CTS mode with 128\-bit SHA\-256 HMAC
T}
_
T{
arcfour\-hmac rc4\-hmac arcfour\-hmac\-md5
T}	T{
RC4 with HMAC/MD5 (deprecated)
T}
_
T{
arcfour\-hmac\-exp rc4\-hmac\-exp arcfour\-hmac\-md5\-exp
T}	T{
Exportable RC4 with HMAC/MD5 (weak)
T}
_
T{
camellia256\-cts\-cmac camellia256\-cts
T}	T{
Camellia\-256 CTS mode with CMAC
T}
_
T{
camellia128\-cts\-cmac camellia128\-cts
T}	T{
Camellia\-128 CTS mode with CMAC
T}
_
T{
des3
T}	T{
The triple DES family: des3\-cbc\-sha1
T}
_
T{
aes
T}	T{
The AES family: aes256\-cts\-hmac\-sha1\-96, aes128\-cts\-hmac\-sha1\-96, aes256\-cts\-hmac\-sha384\-192, and aes128\-cts\-hmac\-sha256\-128
T}
_
T{
rc4
T}	T{
The RC4 family: arcfour\-hmac
T}
_
T{
camellia
T}	T{
The Camellia family: camellia256\-cts\-cmac and camellia128\-cts\-cmac
T}
_
.TE
.sp
The string \fBDEFAULT\fP can be used to refer to the default set of
types for the variable in question.  Types or families can be removed
from the current list by prefixing them with a minus sign ("\-").
Types or families can be prefixed with a plus sign ("+") for symmetry;
it has the same meaning as just listing the type or family.  For
example, "\fBDEFAULT \-rc4\fP" would be the default set of encryption
types with RC4 types removed, and "\fBdes3 DEFAULT\fP" would be the
default set of encryption types with triple DES types moved to the
front.
.sp
While \fBaes128\-cts\fP and \fBaes256\-cts\fP are supported for all Kerberos
operations, they are not supported by very old versions of our GSSAPI
implementation (krb5\-1.3.1 and earlier).  Services running versions of
krb5 without AES support must not be given keys of these encryption
types in the KDC database.
.sp
The \fBaes128\-sha2\fP and \fBaes256\-sha2\fP encryption types are new in
release 1.15.  Services running versions of krb5 without support for
these newer encryption types must not be given keys of these
encryption types in the KDC database.
.SH KEYSALT LISTS
.sp
Kerberos keys for users are usually derived from passwords.  Kerberos
commands and configuration parameters that affect generation of keys
take lists of enctype\-salttype ("keysalt") pairs, known as \fIkeysalt
lists\fP\&.  Each keysalt pair is an enctype name followed by a salttype
name, in the format \fIenc\fP:\fIsalt\fP\&.  Individual keysalt list members are
separated by comma (",") characters or space characters.  For example:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
kadmin \-e aes256\-cts:normal,aes128\-cts:normal
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
would start up kadmin so that by default it would generate
password\-derived keys for the \fBaes256\-cts\fP and \fBaes128\-cts\fP
encryption types, using a \fBnormal\fP salt.
.sp
To ensure that people who happen to pick the same password do not have
the same key, Kerberos 5 incorporates more information into the key
using something called a salt.  The supported salt types are as
follows:
.TS
center;
|l|l|.
_
T{
normal
T}	T{
default for Kerberos Version 5
T}
_
T{
norealm
T}	T{
same as the default, without using realm information
T}
_
T{
onlyrealm
T}	T{
uses only realm information as the salt
T}
_
T{
special
T}	T{
generate a random salt
T}
_
.TE
.SH SAMPLE KDC.CONF FILE
.sp
Here\(aqs an example of a kdc.conf file:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
[kdcdefaults]
    kdc_listen = 88
    kdc_tcp_listen = 88
[realms]
    ATHENA.MIT.EDU = {
        kadmind_port = 749
        max_life = 12h 0m 0s
        max_renewable_life = 7d 0h 0m 0s
        master_key_type = aes256\-cts\-hmac\-sha1\-96
        supported_enctypes = aes256\-cts\-hmac\-sha1\-96:normal aes128\-cts\-hmac\-sha1\-96:normal
        database_module = openldap_ldapconf
    }

[logging]
    kdc = FILE:/usr/local/var/krb5kdc/kdc.log
    admin_server = FILE:/usr/local/var/krb5kdc/kadmin.log

[dbdefaults]
    ldap_kerberos_container_dn = cn=krbcontainer,dc=mit,dc=edu

[dbmodules]
    openldap_ldapconf = {
        db_library = kldap
        disable_last_success = true
        ldap_kdc_dn = "cn=krbadmin,dc=mit,dc=edu"
            # this object needs to have read rights on
            # the realm container and principal subtrees
        ldap_kadmind_dn = "cn=krbadmin,dc=mit,dc=edu"
            # this object needs to have read and write rights on
            # the realm container and principal subtrees
        ldap_service_password_file = /etc/kerberos/service.keyfile
        ldap_servers = ldaps://kerberos.mit.edu
        ldap_conns_per_server = 5
    }
.ft P
.fi
.UNINDENT
.UNINDENT
.SH FILES
.sp
\fB@LOCALSTATEDIR@\fP\fB/krb5kdc\fP\fB/kdc.conf\fP
.SH SEE ALSO
.sp
krb5.conf(5), krb5kdc(8), kadm5.acl(5)
.SH AUTHOR
MIT
.SH COPYRIGHT
1985-2023, MIT
.\" Generated by docutils manpage writer.
.
